Surgeons who operate in the lower abdomen or pelvic area face a number of challenges. In open surgery, or a laparotomy, surgeons sometimes must make a large incision in the belly of the patient to access the bowel and safely displace or shield it out of the surgical area and into the upper abdomen. The large incision is traumatic and increases blood loss, recovery time, and the risk of complications.
In addition, to operate in the lower abdomen or pelvic area surgeons must employ the steep trendelenburg position, which presents a number of problems and risks for healthy patients and enhanced risks for the obese, geriatrics, diabetics, and patients with cardiovascular or respiratory problems. In the trendelenburg position, a patient lies at an incline so that their feet are elevated at an angle above their head, typically 10 to 30 degrees, sometimes 45 degrees. Some common position ranges, for example, include 10 to 15 degrees for open surgery, 10 to 20 degrees for laparoscopic surgery, and 15 to 45 degrees for robotic surgery.
At such inclines, gravity exerts a downward force upon the bowel, such that the bowel falls toward the upper abdomen, thereby leaving a space in the pelvic cavity or lower abdomen 34. FIGS. 5 and 6 show a cross-section of the patient and the effect of transitioning from a flat reclined position (FIG. 5) to a steep trendelenburg position (FIG. 6). Patients typically remain in this position for the duration of the surgery, which may be several hours.
The steeper trendelenburg positions (or angles) may present problems and risks for otherwise healthy patients and enhanced risks for the obese, geriatrics, diabetics, and patients with cardiovascular or respiratory problems. The patient may experience respiratory and cardiovascular challenges, facial edema, intraocular pressure, or stagnation of the blood in the head because of the gravitational force exerted upon the bodily organs which are in reversed orientation. The patient may, in the worst instances, even experience a pulmonary edema, aneurysm, or increased risk of stroke. The trendelenburg position also may concentrate anesthesia in the head by increased blood flow and stasis, which increases risks from anesthesia.
The steep trendelenburg position also strains the lower extremities, which are tied down by stirrups to prevent the patient from sliding off the inclined operating table. For the obese, there is a greater risk of blood stasis in the legs and the feet in addition to compression or injury to the peroneal nerve resulting in foot drop or paralysis.
The steep trendelenburg position also compromises surgical safety. Patients can experience cephalic sliding (i.e., sliding down the operating table head first) during a surgical procedure. Cephalic sliding compromises the surgeon's ability to perform surgery with precision and accuracy, and this heightens the risk of accidental injury to internal organs.
Finally, the steep trendelenburg position may not be steep enough to keep the bowel in the upper abdomen. Sometimes, the bowel may slide to the lower abdomen or pelvic area during surgery. This often happens when patient's anesthesia begins to wear off and the patient begins to breathe, which is not an uncommon occurrence. The inhalations counteract the force of gravity, and sometimes the inhalations push the bowel from the upper abdomen back into the pelvic area or lower abdomen. Sliding of the bowel increases the risk of surgical error or injury, particularly when the surgeon is using sharp surgical tools, cauterizers, and lasers.
Improvements to accessibility of the abdominal and pelvic area during surgery without compromising patient safety are therefore desirable.